The Shankill Road was a crisscross of flags and bunting last week, in part left over from the Queen's "handshake" visit to Belfast a few days earlier, but also in readiness for the culmination on Thursday of the summer marching season. Bands will parade on the Twelfth, when Protestant Orangemen commemorate the battle of the Boyne and everyone, whatever their creed or politics, has a national holiday and hopes for calm.

Pipe or flute bands are far from the only kind of music associated with Northern Irish Protestants or loyalists but they tend to be what we hear about. Nor is the tradition of Irish dance and folk music entirely the province of Roman Catholics or republicans, even if those distinctions were once more potently clear.

Last week at the Mac, the stunning new Metropolitan Arts Centre in the city's cathedral quarter, the cross-community 2012 McCracken summer school was launched to the sound of fiddle and bodhrán. Aimed at uniting "Gaels" of all ages and backgrounds, it will take place in mid-July in north Belfast, known as the "killing fields" during the Troubles. A bold highlight will be an evening of Scottish and Irish music held in the former Crumlin Road prison, closed since 1996 but now being restored and, unimaginably, a tourist attraction. This gloomy, basalt Victorian monument may be grade A-listed but no one needs long memories to recall its notorious past.

On the same day at the multipurpose Mac another event, even more remarkable though not so contentious, was taking place. Five opera premieres, described as "snapshots of lives on the edge", were staged by Northern Ireland Opera, with music by five Northern Irish composers at various stages in their careers, working with leading contemporary playwrights. Musicians from the Ulster Orchestra and a talented cast of nine singers from across Ireland performed these compact, hard-hitting works conducted by Fergus Sheil and directed by Rachel O'Riordan.

Founded less than two years ago, NI Opera is run by a permanent staff of four, steered by the inspirational artistic director Oliver Mears. Why was it set up? Opera is more associated with the south – think of Molly Bloom and all the opera references in James Joyce – and especially with Wexford, a magnet for connoisseurs of rare repertoire.

Opera endeavours in the north, such as the "country house" seasons at Castle Ward on Strangford Lough, have tended to be short-lived, whether for reasons of finance, political difficulties or lack of interest. That said, Pavarotti made his UK debut in 1963 at the beautiful Grand Opera House in Belfast, a Frank Matcham theatre blighted by frequent bomb damage since 1969 but now restored to its former glory.

The answer, in part, is that the Arts Council of Northern Ireland encouraged the company's foundation in direct response to the Good Friday agreement of 1998 and the St Andrew's agreement of 2006. Buried in the legislation are specifications about cultural activities being available to all. This will come as a surprise to most of us reliant on the narrow focus of news reports.

In need of background and context, I spoke to Fionnuala Jay-O'Boyle, a NI Opera board member who trained as a soprano but instead pursued a non-musical career. She sees the new opera company as part of the change sweeping through the region: "It's putting the seal on a new optimism, shaking off old, painful shackles at last. Belfast is a resurgent city, physically and psychologically – though it's been a slow process until this renewal could happen. The Mac is a shining example of a new cultural confidence. There's been a cultural drain in the last few decades, especially of young singers. They've tended to go and study at the conservatoires in Glasgow or Manchester and then they're gone. Now they're coming back."

NI Opera has already made its mark with a site-specific Tosca in Derry and a critically acclaimed Turn of the Screw (touring to Buxton festival next week). In this bouquet of new works, each opera was skilful, provoking laughter as well as sorrow and, at an average duration of 10 minutes, never a moment too long. A steeply raked single set, designed by Gary McCann, cleverly offered versatility.

The powerful opener was Our Day by Conor Mitchell and Mark Ravenhill. Set in Belfast in 1972, arguably the worst year of the violence, it reflects on the strangeness of the day Mary Peters – who, at 72, is now Lord Lieutenant of Belfast – won a gold medal at the Munich Olympics and the violence paused. Ravenhill's clear, readily comprehensible text captures a Samaritan act of kindness when a mother (an excellent Giselle Allen) takes a dying soldier into her home. Mitchell's high vocal lines are offset by the sombre orchestral timbres of low strings and woodwind. The mood is tender and disturbing.

In pulsating contrast, Jackie's Taxi by Ed Bennett and Stacey Gregg mixes playfulness with urban vice. Brassy Jackie in lurid velveteen catsuit, four "hoods" and a policeman collide in the low-life, druggy world of a none too regular minicab office. The score freely embraces keyboards and drum-kit funk, siren-like brass and some witty vocal ensembles. "But Belfast is changing," sings a solo voice. "So it is, so it is," responds a mini chorus, cheeky and inane.

Based on a true event, The Girl Who Knew She Could Fly, by Christopher Norby and Frank McGuinness, exposes us to the intimate, unending grief of parents (Doreen Curran and Paul Carey Jones) mourning their dead daughter, a student who jumped from a motorway bridge in Dublin. This piece was so anguished, more lament than drama, that it needed more space around it than the context of five contrasting works could allow.

Driven, a monologue by Deirdre McKay and actor-writer Richard Dormer, changed the mood yet again. Eamonn Mulhall was outstanding as the charismatic Robert Blair "Paddy" Mayne, the Irish second world war hero with a destructive, drunken streak. The title refers both to his personality and his last, fatal journey. Amid the whirl of musical colours from these five operas, his wistful "I'm coming home" twinned with a poignant, muted trumpet solo sticks in the mind.

As an upbeat finale, Brian Irvine's ensemble piece May Contain Flash Photography, eclectic in musical style with some nice close harmony, entered the sleazy fun of a lottery game show where a terrible family sit on a sofa and dream, hopelessly, of changing their lives with a lucky win. Owen McCafferty, whose Scenes from the Big Picture enjoyed success at the National Theatre, provided a sharp script.

All five works will be performed in concert in London at the PRS/London 2012 New Music 20x12 weekend at the Southbank on Friday. NI Opera's next event is Britten's Noye's Fludde, with perfect logic taking place in Belfast zoo and using local schoolchildren, many from Northern Ireland's Chinese community – the region's largest ethnic minority. It then travels to Beijing, apparently China's first exposure to a production of a Britten opera. Next year, with an ambitious Flying Dutchman, Northern Ireland will have its first Wagner staging for half a century. As far as I know it's not time- or site-specific, but with this ingenious company it's all in the lap of the gods.

A performance of Our Day, recorded at the Mac, Belfast on 28 June, will be broadcast on Radio 3 on 21 July